The present invention relates to electronic imaging devices, and more particularly to semiconductor processing methods for producing varieties of otherwise ordinary and inexpensive CCD array devices that can operate faster than one hundred frames-per-second.
U.S. Pat. No. 6,255,134 B1, issued Jul. 3, 2001, to one of the present inventors, Toshikazu Hori, describes a modification to an otherwise standard CCD imaging device that can improve its performance. Such comprises modifying the optical mask of an otherwise ordinary and inexpensive CCD integrated circuit to darken a majority of the active imaging photocells. The CCD integrated circuit is operated at near its maximum horizontal and vertical clock rates, but multiple image frames are defined within the one previous active photocell array field. The added dark areas in the optical mask protect the recent frames still in transit within the active array area from being double exposed and thus corrupted. The serial output of the thus-modified CCD device is reinterpreted to include more frames than originally at a multiple equal to the original array dimension divided by the new array dimension (mxc2x7n/mxe2x80x2xc2x7nxe2x80x2). So a modified CCD array that used only one-fourth of the original active area could be operated at four times the original frame rate. Such Patent is incorporated herein by reference.
A certain minimum production quantity is necessary to justify changing or adding a new mask to a commodity CCD device. When the needed volumes of pieces are too low to interest a semiconductor producer, something else is needed to accomplish the same ends as described in the above Patent.
It is therefore an object of the present invention to provide a CCD imaging device that can operate at frame rates over one hundred frames-per-second.
It is another object of the present invention to provide a CCD imaging device that is inexpensive to manufacture.
It is a further object of the present invention to provide a method for modifying an inexpensive CCD imaging device that can be done economically in low production volumes.
Briefly, a CCD imaging device embodiment of the present invention comprises attaching a fiberoptic block to an otherwise ordinary and inexpensive CCD integrated circuit. A part of the fiberoptic block is occluded so as to darken a majority of the active imaging photocells. The CCD integrated circuit is operated at near its maximum horizontal and vertical clock rates, but multiple image frames are defined within the one previous active photocell array field. The added dark areas in the optical field protect the recent frames still in transit within the active array area from being double exposed and thus corrupted. The serial output of the thus-modified CCD device is reinterpreted to include more frames than originally at a multiple equal to the original array dimension divided by the new array dimension (mxc2x7n/mxe2x80x2xc2x7nxe2x80x2). Such a modified CCD array uses only one-fourth of the original active area, and is operable at a multiple of the original frame rate.
An advantage of the present invention is that a CCD imaging device is provided that can operate at frame rates over one hundred frames-per-second and is inexpensive to manufacture.
Another advantage of the present invention is that a CCD imaging device with a very fast frame rate is obtainable by attaching a fiberoptic block aperature to an otherwise ordinary and commodity type CCD imaging device.
These and other objects and advantages of the present invention will no doubt become obvious to those of ordinary skill in the art after having read the following detailed description of the preferred embodiments which are illustrated in the drawing figure.